This invention relates to an integrated process reactor system for converting oxygenates such as methanol and dimethyl ether (DME) to liquid hydrocarbons. The oxygenate feedstock is contacted with a zeolite catalyst in a reaction zone to distillate and/or gasoline through an intermediate olefinic material.
It is known to contact an oxygenate feedstock with a dehydration catalyst to produce lower olefins, which may be employed as starting materials for producing gasoline. The C.sub.3 -C.sub.4 olefins are mixed with isobutane and directed to an acid alkylation reaction zone to yield a valuable alkylate gasoline.
The following patents are examples of related prior art. Their disclosures are incorporated herein by this reference to them.
U.S. Pat. No. 3,972,958 (Garwood et al) discloses a process for converting coal to high octane gasoline which includes the step of alkylating the C.sub.3 -C.sub.4 olefins with isobutane.
U.S. Pat. No. 4,211,885 (Banks) discloses a process for producing high octane gasoline which includes the step of alkylating a butenes stream with isobutane.
The foregoing patents do not teach the concept of providing an alkylation unit with a feedstock derived from a combination of an MTG (methanol to gasoline) reactor and an MTO (methanol to olefin) reactor.
In a typical fixed-bed MTG process relatively large amounts of isobutane are produced, eg., about 8% by weight of hydrocarbons product. In the past, it has been the practice to recover the isobutane fraction without an immediate upgrading step. In fluidized bed MTG operations, isobutane production may be balanced with C.sub.3 -C.sub.4 olefin production to provide a stoichiometric ratio for separation and upgrading, or excess isobutane byproduct may be made.